There is known a workpiece feed for a sewing machine comprising a pair of feet both of which are reciprocal toward and away from a support surface and one of which, the feed foot, is also slidable along the support surface so as incremently to advance the workpiece toward the sewing station on the support surface. Each of the feet is connected via a respective rod to a respective pivot of a ternary link whose other pivot is connected to a crank driven by the drive shaft of the sewing machine so that the ternary link is displaced toggle-fashion between a pair of overcenter positions in each of which a respective one of the feet is pressed against the workpiece and the surface. Such a system has the considerable disadvantage that the feet are displaced with relatively high speed against the workpiece, so it is necessary to provide a certain amount of lost motion in the system such that the two feet will both simultaneously engage the workpiece for a brief instant before each one is lifted. Thus the displacement speed of the feet is at a maximum just at that instant when the feet engage the workpiece and press it against the surface.
Such a system has the considerable disadvantage that the feet pound against the workpiece and frequently damage it. In addition the sewing machine so equipped creates a considerable amount of noise and vibration and goes out of adjustment quickly. In addition due to the violence with which the feet strike the fabric workpiece they frequently bounce up briefly and allow this workpiece to move on the support surface out of alignment with its desired position. Thus it is necessary to provide rather complicated and expensive damping arrangements to prevent the reciprocating feet from damaging the workpiece and vibrationally damaging the machine. Of course it is also possible to simply operate the sewing machine at slower speed so as to avoid these difficulties, however this considerably cuts production efficiency and therefore is undesirable.